Method for GNSS coexistence

ABSTRACT

A method for operating a wireless transmitter and a global navigation satellite (“GNSS”) receiver coexistent in a mobile wireless device. A mobile wireless device includes a GNSS receiver and a wireless networking system. The wireless networking system includes a wireless transmitter. The wireless transmitter provides a first interference level signal to the GNSS receiver. The first interference level signal indicates a level of interference that the GNSS receiver can expect due to operation of the transmitter. A priority signal is asserted if the processing of navigation signals in the GNSS receiver takes precedence over wireless transmitter transmissions.

This application is a Divisional of and claims priority to U.S. patentSer. No. 12/394,404 filed on Feb. 27, 2009 which claims priority toprovisional patent application 61/035,097, filed on Mar. 10, 2008,entitled “Method and System for GNSS Coexistence.” Said applicationsherein incorporated by reference

BACKGROUND

As wireless technologies proliferate, mobile wireless devicesincorporate a multiplicity of different wireless standards. For example,a cellular telephone can accommodate a cellular network (e.g., UniversalMobile Telecommunications System), a local area network, such as IEEE802.11, and a personal area network (e.g., Bluetooth).

Some mobile devices also utilize receive only networks, such as one ormore of the global navigation satellite systems (“GNSS”). Examples ofGNSS include the Global Positioning System (“GPS”), the GLObalNavigation Satellite System (GLONASS), the Galileo system, theQuazi-Zenith Satellite System (QZSS), and Beidou. GNSS enabled devicescan use the navigation system to provide directions or locationinformation while the device simultaneously accesses one or morewireless networks, for example, to receive a voice call via a cellularnetwork and/or to utilize a Bluetooth headset. Unfortunately, wirelessnetwork access can interfere with GNSS signal reception.

SUMMARY

Various systems and methods for simultaneously utilizing a plurality ofwireless networks colocated in a wireless device are disclosed herein.In accordance with at least some embodiments, a mobile wireless deviceincludes a global navigation satellite system (“GNSS”) receiver and awireless networking system. The wireless networking system includes awireless transmitter. The wireless transmitter provides a firstinterference level signal to the GNSS receiver. The first interferencelevel signal indicates a level of interference that the GNSS receivercan expect due to operation of the transmitter.

In accordance with at least some other embodiments, a method includesdetermining whether a wireless transmitter in a mobile wireless devicehas data to transmit. If the wireless transmitter has data to transmit,then a first interference level signal is asserted by the wirelesstransmitter. The first interference level signal is provided to a GNSSreceiver in the mobile wireless device. Processing of navigation signalsin the GNSS receiver is controlled based, at least in part, on theassertion of the first interference level signal by the wirelesstransmitter. The location of the mobile wireless device is determinedbased on the navigation signal processing.

In accordance with yet other embodiments, a mobile wireless deviceincludes a GNSS receiver that notifies a wireless transmitter colocatedin the mobile wireless device when reception of navigation signals bythe GNSS receiver should take priority over transmissions by thewireless transmitter.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of exemplary embodiments of the invention,reference will now be made to the accompanying drawings in which:

FIG. 1 shows an exemplary wireless network in accordance with variousembodiments;

FIG. 2 shows a block diagram of a global navigation satellite (“GNSS”)receiver and a wireless networking system colocated in a mobile wirelessdevice in accordance with various embodiments;

FIGS. 3A and 3B show signal diagrams of exemplary network transmissionsequences and resulting GNSS system control signals in accordance withvarious embodiments;

FIG. 4 shows a flow diagram for a method for providing GNSS systemcontrol signals in accordance with various embodiments; and

FIG. 5 shows a flow diagram for a method for providing wirelessnetworking system transmitter control signals in accordance with variousembodiments.

NOTATION AND NOMENCLATURE

Certain terms are used throughout the following description and claimsto refer to particular system components. As one skilled in the art willappreciate, computer companies may refer to a component by differentnames. This document does not intend to distinguish between componentsthat differ in name but not function. In the following discussion and inthe claims, the terms “including” and “comprising” are used in anopen-ended fashion, and thus should be interpreted to mean “including,but not limited to . . . . ” Also, the term “couple” or “couples” isintended to mean either an indirect, direct, optical or wirelesselectrical connection. Thus, if a first device couples to a seconddevice, that connection may be through a direct electrical connection,through an indirect electrical connection via other devices andconnections, through an optical electrical connection, or through awireless electrical connection. Further, the term “software” includesany executable code capable of running on a processor, regardless of themedia used to store the software. Thus, code stored in memory (e.g.,non-volatile memory), and sometimes referred to as “embedded firmware,”is included within the definition of software.

DETAILED DESCRIPTION

The following discussion is directed to various embodiments of theinvention. Although one or more of these embodiments may be preferred,the embodiments disclosed should not be interpreted, or otherwise used,as limiting the scope of the disclosure, including the claims. Inaddition, one skilled in the art will understand that the followingdescription has broad application, and the discussion of any embodimentis meant only to be exemplary of that embodiment, and not intended tointimate that the scope of the disclosure, including the claims, islimited to that embodiment.

Disclosed herein are a system and method for operating a globalnavigation satellite system (“GNSS”) receiver and another wirelesstechnology colocated (i.e., located together) in a mobile wirelessdevice. While access to multiple wireless networks and systems providesa number of benefits, interference between different technologies canmake simultaneous operation of different wireless technologies colocatedin a mobile device problematic. For example, out of band emissions byone technology can saturate the receiver of another technology.Moreover, strong signals can create reliability issues in low noiseamplifiers. Rejection filter designs may have to provide 40-55 dB ofattenuation or more, which is difficult in practice. Embodiments of thepresent disclosure allow a GNSS system to coexist in a mobile wirelessdevice with one or more other wireless networking technologies, such asWiMAX (IEEE 802.16), WLAN (IEEE 802.11), long-term evolution (“LTE”)networks, wireless USB, Bluetooth, etc. Embodiments includeinter-technology signaling mechanisms that allow a GNSS system toidentify and/or control periods of possible interference by othertechnologies. Having identified a period of potential interference, theGNSS system can mitigate the effects of the interference to providereliable navigation.

FIG. 1 shows an exemplary wireless network 100 in accordance withvarious embodiments. The wireless network 100 includes an access point102, and a mobile wireless device 104. As illustrated, the wirelessnetwork 100 also optionally includes mobile wireless devices 106 and108. In practice, a wireless network may include one or more mobilewireless devices. The wireless mobile device 104 transmits data to andreceives data from the access point 102. The access point 102 can alsobe referred to as a base station, a node B, etc. Some embodiments of thewireless network 100 can employ ad-hoc networking, and may not includethe access point 102. Instead, the mobile wireless devices 104, 106, 108communicate directly with one another. Exemplary mobile wireless devicesinclude cellular telephones, personal digital assistants, personalcomputers, navigation devices, etc.

The mobile wireless device 104 includes a GNSS system 110 fordetermining the location of the device 104. The GNSS system 110 canoperate on GPS, GLONASS, or any other positioning system. Someembodiments of the mobile wireless receiver 104 can include a pluralityof GNSS systems 110, each operating on different positioning networks.The mobile wireless device 104 also includes a wireless networkingsystem 112, which can be, for example, an IEEE 802.11 wireless LAN,WiMAX, Bluetooth, a cellular technology such as LTE, etc. The wirelessnetworking system 112 includes a transmitter that when active canproduce out of band emissions that interfere with reception ofnavigation signals provided by a navigation transmitter, such as apositioning satellite. In some embodiments, the mobile wireless device104 can include multiple wireless networking systems 112, at least oneof which can operate concurrently with the GNSS system 110. Embodimentsencompass all combinations of GNSS systems 110 and wireless networkingsystems 112 colocated in a mobile wireless device 104.

Embodiments of the GNSS receiver 110 and the wireless networking system112 included in the mobile wireless device 104 provide communicationsignals passing between the GNSS system 110 and the wireless networkingsystem 112 that inform the GNSS system 110 of time intervals wheninterference is likely. Some embodiments also provide signals from theGNSS system 110 to the wireless networking system 112 that inform thewireless networking system 112 of intervals when the GNSS system 110desires reduced interference. The GNSS system 110 and the wirelessnetworking system 112 thus coordinate operations to reduce interferenceto navigation signal reception, and provide improved GNSS system 110performance.

FIG. 2 shows a block diagram of a GNSS system 110 and a wirelessnetworking system 112 colocated in a mobile wireless device 104 inaccordance with various embodiments. The wireless networking system 112includes a transmitter 206, a receiver 204 and a controller 208. Thetransmitter 206 transmits signals over the wireless network, and thereceiver 204 receives signals transmitted over the wireless network. Thetransmitter 206 and the receiver 204 include a variety of componentsthat are not shown, for example, modulator/demodulator, encoder/decoder,amplifiers, filters, etc.

The receiver 204 and the transmitter 206 exchange information andcontrol with the controller 208. In some embodiments, the controller 208can be integrated into the receiver 204 and/or the transmitter 206. Insome embodiments, the controller 208 may be separate from the receiver204 and/or the transmitter 206. The controller 208 receives informationfrom the transmitter 206, such as notification of transmitter activityand/or expected transmitter activity and provides transmitter activityinformation to the GNSS system 110. In some embodiments, transmitteractivity state information may include, for example, transmitter active,transmitter inactive, and transmission pending.

Similarly, the controller 208 receives information from the receiver204, such as notification of signal detection and provides receiveractivity information to the GNSS system 110. The controller 208 can alsoprovide information, such as a request for reduced interference, to thetransmitter 206.

The GNSS system 110 includes a GNSS receiver 214 and a controller 212.The GNSS receiver 214 receives and processes navigation signals todetermine a location of the mobile wireless device 104. The GNSSreceiver 214 provides information to and receives control from thecontroller 212. The GNSS receiver 214 may, for example, notify thecontroller 212 when the GNSS receiver 214 desires improved navigationsignal fidelity, or when reduced navigation signal fidelity isallowable. The controller 212 may provide the GNSS receiver 214 withinformation indicating an expected level of interference by the wirelessnetwork, based, for example, on information received from the wirelessnetworking system 112.

The GNSS system 110 and the wireless networking system 112 communicatewith each other to provide control over wireless network (e.g.,transmitter 204) interference with GNSS navigation signal reception. Theillustrated embodiment includes a first signal “S1” 216, a second signal“S2” 218, and a priority signal 220. Note that in embodiments includingmultiple wireless networking systems 112 and/or multiple GNSS systems110, each wireless networking system 112 can provide a separate set ofcontrol signals to each GNSS system 110 to facilitate operation wheneach GNSS system 110 and/or each wireless networking system 112 operatesin a different frequency band.

The wireless networking system 112 can assert the signals S1 216 and S2218 to indicate a level of interference that the GNSS system 110 canexpect due transmissions on the wireless network 100. In someembodiments, the signal S1 216 can indicate that the transmitter 206,colocated with the GNSS system 110 is active and transmitting data viathe wireless network. In some embodiments, the signal S2 218 canindicate that the network receiver 204 is active (i.e., processing adetected transmission), or that either the network receiver 204 isactive or another network device (e.g., access point 102) istransmitting.

In some embodiments, the signals S1 216 and S2 218 can provide moredetailed information about interference levels than is described above.For example, the signal S1 216 can indicate the power applied by thetransmitter 206 during transmission, and the signal S2 218 can indicatea signal-to-noise ratio measurement of over-the-air transmissions toindicate the amount of interference the GNSS system 110 can expect.

The GNSS system 110 can apply the information provided in the S1 216and/or S2 218 signals in a variety of ways. Embodiments can employ theinformation to mitigate the effects of navigation processing on receiver204 signal reception, or to mitigate the effects of network 100interference on navigation signal reception. In some embodiments, whenthe signals S1 216 and/or S2 218 indicate that the wireless network 100is causing little or no interference, then the GNSS system 110 canprocess navigation signals continuously and without any specialinterference mitigation. In some embodiments, when the signals S1 216and/or S2 218 indicate some level of interference the GNSS system 110can either process the satellite signals normally, or not process thesatellite signals during the time of interference, or use aninterference mitigation technique during the time of interference. Forexample, for navigation signals that use a spread spectrum type ofsignal design (e.g., code-division multiple access (“CDMA”)), if thefrequency interference is limited to only a portion of the signalbandwidth then a filter can be used to remove the interference and theGNSS system 110 can process the remainder of the signal spectrumnormally—albeit with a lower signal-to-noise ratio (“SNR”).

In an embodiment wherein the network 100 is, for example, a wirelesslocal area network (“WLAN”), packets transmitted over the network 100are broadcast packets, and therefore the packets are received by allwireless devices in the network including the wireless networking system112. The wireless networking system 112 can assert an S2 218 signal tothe GNSS system 110 regardless of whether a packet transmitted by adifferent mobile wireless device 106, 108 or the access point 102 isdestined for the device 104. If a transmitted packet is destined for thedevice 104, the wireless networking system 112 will preferably assertthe signal S1 216 to the GNSS system 110 only if an acknowledgment orother responsive packet is to be transmitted by the transmitter 206. Inother words, the signal S1 216 may be asserted only when the wirelessnetworking system 112 colocated with the GNSS system 110 will betransmitting.

In such an embodiment, the GNSS system 110 can receive navigationsignals for a time duration indicated in the transmitted WLAN packet(e.g., in the PHY preamble). If the transmitted WLAN packet is notdestined for the wireless networking system 112, then, the time durationduring which the GNSS system 110 can receive navigation signals can beadjusted, for example, based on a network allocation vector (“NAV”) readfrom the packet.

FIG. 3A illustrates an example where the access point 102 istransmitting to a mobile wireless device other than the device 104, forexample transmitting to the wireless mobile device 108. The access point102 first transmits a request to send (“RTS”). The device 104 detectsthe RTS and asserts signal S2 218 for the duration of the RTS. When thereceiver 204 decodes the RTS packet and determines that the transmissionis not destined for the mobile wireless device 104, the S2 signal 218can be negated. The signal S1 216 is negated throughout the illustratedsequence because the device 104 is not transmitting.

FIG. 3B illustrates an example where the access point 102 istransmitting to the mobile wireless device 104. The access point 102first transmits an RTS. The device 104 detects the RTS and assertssignal S2 218 for the duration of the RTS. The device 104 decodes theRTS packet and determines that the transmission is destined for thedevice 104. The device 104 transmits a clear to send (“CTS”) packet ashort inter-frame space (“SIFS”) interval after the RTS. The S1 signal216 is asserted during the CTS transmission. The access point 102 thentransmits a series of media access control protocol data units(“MPDUs”). As each MPDU is processed by the receiver 204, the wirelessnetworking system 112 asserts S2 218. Similarly, S2 218 is assertedduring reception of the block acknowledge request (“BAR”). Following BARreception, S1 216 is asserted during transmission of the blockacknowledge (“BA”).

In some embodiments, the SIFS intervals may not be considered. In suchembodiments, when the receiver 204 decodes the RTS packet, the NAV canbe read from the RTS packet, and the signal S2 218 extended by the timeindicated in the NAV (i.e., for the duration of TXOP).

In an embodiment wherein the wireless networking system 112 is aBluetooth system, voice over internet protocol (“VOIP”) traffic isperiodic with active intervals of 1.25 milli-seconds (“ms”) and inactiveintervals of 2.5 ms. Thus, an embodiment may assert S1 216 for a periodof 1.25 ms and assert S2 218 for a period of 2.5 ms. The time period ofS1 216 assertion can be further reduced to 0.625 ms. For other types oftraffic (i.e., non-VOIP traffic), the duration of S1 216 and S2 218signals will depend on the characteristics of the traffic.

In an embodiment wherein the wireless networking system 112 is a WiMAXsystem, when the mobile wireless device 104 has data to transmit via thewireless networking system 112, the S1 216 signal can be asserted forthe duration of the transmission. Generally, the transmit duration is nomore than a few milliseconds.

Similarly, other wireless technologies, that may be either time orfrequency division duplexed, such as LTE or Global System for MobileCommunications (“GSM”), that discontinuously transmit can coexist withthe GNSS system 110 as described above. As long as the communicationbetween network stations, for example mobile wireless device 104 andaccess point 102 includes non-transmission intervals, the signals S1 216and/or S2 218 can be used to facilitate coexistence.

Referring again to FIG. 2, the GNSS system 110 provides a signalPriority 220 to the wireless networking system 112. In some embodiments,the Priority 220 signal can notify the wireless networking system 112that the GNSS system 110 desires reduction of interference. The GNSSsystem 110 may need reduced interference when, for example, the receivednavigation signals are weak, such as when obstructed by buildings orother topographic features. The Priority 220 signal notification cancause the wireless networking system 112 to change its behavior, forexample, to transmit at a lower power level, thus reducing interference.

Similarly, the GNSS system 110 may use the Priority 220 signal to notifythe wireless networking system 112 that the system 112 need not modifyits behavior to reduce interference. For example, if the GNSS system isproviding route guidance to a driver, and the next turn is many milesaway, the GNSS system 110 may not need to continuously receive andprocess navigation signals.

Various components of the wireless networking system 112 and the GNSSsystem 110, including at least some portions of the receiver 204, thetransmitter 206, the controller 208, the receiver 214 and the controller212 can be implemented using a processor and software programming thatcauses the processor to perform the operations described herein. Inparticular, software programming can cause a processor to provideinterference indications S1 216 and/or S2 218 to the GNSS system 110 andpriority indications 220 to the wireless networking system 112, andattendant transmission and navigation processing behavior changes asdescribed herein. Suitable processors include, for example,general-purpose processors, digital signal processors, andmicrocontrollers. Processor architectures generally include executionunits (e.g., fixed point, floating point, integer, etc.), storage (e.g.,registers, memory, etc.), instruction decoding, peripherals (e.g.,interrupt controllers, timers, direct memory access controllers, etc.),input/output systems (e.g., serial ports, parallel ports, etc.) andvarious other components and sub-systems. Software programming can bestored in a computer readable medium. Exemplary computer readable mediainclude semiconductor memory, optical storage, and magnetic storage.

Some embodiments can implement the functionality described herein usingdedicated circuitry. Some embodiments may use a combination of dedicatedcircuitry and software executed on a processor. Selection of a hardwareor software implementation is a design choice based on a variety offactors, such as cost and the ability to incorporate changed oradditional functionality in the future.

In at least some embodiments, the wireless networking system 112 and theGNSS system 110 may share some hardware resources, such that at leastsome parts of the systems 110, 112 may not operate concurrently. In suchembodiments, the S1 216, and/or S2 218, and/or Priority 220 signals maybe inputs to arbitration logic (i.e., an arbiter) that determines whichsystem can use the shared resource. The arbiter can provide signals tothe systems 110, 112 and/or the shared resource indicating to whichsystem 110, 112 the resource is allocated. For example, if the GNSSsystem 220 asserts the Priority 220 signal, a shared resource may beallocated to the GNSS system 220. In at least some embodiments, thearbiter can be included in controller 208 and/or controller 212.

In an exemplary embodiment, the wireless network receiver 204 uses atechnology similar to that used by the GNSS receiver 214. This canoccur, for example, if the wireless network 100 and the navigationsignal source (e.g., a navigation satellite) transmit CDMA signals. AGNSS receiver 214 can include a plurality of correlators to enable fastprocessing of the CDMA signals transmitted by a GNSS satellite. When thewireless network 100 is active (e.g., S2 is asserted), then at leastsome of correlators of the GNSS receiver 214 can be allocated to thewireless network receiver 204. Even in embodiments wherein the GNSSsystem 110 and the wireless networking system 112 are not based on thesame technology (e.g., both are not CDMA based), the mobile wirelessdevice 104 can benefit from sharing a hardware resource across colocatedtransmitters and/or receivers, for example, to reduce hardware costs.

FIG. 4 shows a flow diagram for a method for providing GNSS system 110control signals in accordance with various embodiments. Though depictedsequentially as a matter of convenience, at least some of the actionsshown can be performed in a different order and/or performed inparallel. Additionally, some embodiments may perform only some of theactions shown. In some embodiments, the operations of FIG. 4, as well asother operations described herein, can be implemented as instructionsstored in a computer readable medium and executed by a processor.

In block 402, a mobile wireless device 104 including a GNSS system 110and a wireless networking system 112 is operating. If the network 100 isinactive (i.e., no signals are being transmitted over the network), thenin block 404, the wireless networking system 112 notifies the GNSSsystem 112 that no interference from the network should be expected. Insome embodiments, the wireless networking system 110 can assert the S2218 signal to perform such notification. When no interference isexpected the GNSS receiver 110 can process received navigation signalscontinuously and without interference mitigation.

If, in block 402, the network 100 is active (i.e., data is beingtransmitted), the wireless networking system 112 checks, in block 406,for reception of signals transmitted by other network devices 102, 106,108. If another device 102, 106, 108 is transmitting, then, in block408, the wireless networking system 112 determines the duration of thetransmission. In some embodiments of the network 100, some transmissionsmay be of fixed duration and/or the duration of some transmissions maybe defined in a transmitted packet. In block 410, the wirelessnetworking system 112 notifies the GNSS system 110 of an interferencelevel that can be expected during the transmission. In some embodiments,no interference may be indicated when other devices 102, 106, 108 aretransmitting but the device 104 is not transmitting. In otherembodiments, some level of interference may be indicated based on, forexample, the frequency band and/or power level of the received signal.When little or no interference is expected the GNSS receiver 110 canprocess received navigation signals continuously and withoutinterference mitigation.

In block 412, the wireless networking system 112 determines whether thetransmission detected in block 406 is complete. If the transmission iscomplete, the method continues in block 402, otherwise the methodcontinues to check for transmission completion in block 412.

If, in block 406, the wireless networking system 112 is not receiving asignal (i.e., no signal is being transmitted by another device 102, 106,108), then in block 414, the wireless networking system 112 determineswhether the transmitter 206 is transmitting. If the transmitter 206 isidle, then in block 404, the wireless networking system 112 informs theGNSS system 110 that no interference is expected.

If, in block 414, the transmitter 204 is active, then, in block 416, thewireless networking system 112 determines the duration of thetransmission. The GNSS system 110 is notified, in block 418, of thelevel of interference the transmission is expected to present toreception of navigation signals. In some embodiments, the notificationmay simply indicate that the transmitter 206 is active. In someembodiments, the notification may be based on transmitter 206 outputpower and/or transmit frequency bands, and/or other measurements oftransmission interference with navigation signals. The GNSS system 110can ignore the notification, and/or discontinue navigation signalprocessing, and/or implement interference mitigation measures such asfiltering in various embodiments in accordance with the anticipatedinterference level and the capabilities of the GNSS system 110.

In block 420, the wireless networking system 112 determines whether thetransmission detected in block 414 is complete. If the transmission iscomplete, the method continues in block 402, otherwise the methodcontinues to check for transmission completion in block 420.

FIG. 5 shows a flow diagram for a method for providing wirelessnetworking system transmitter 206 control signals in accordance withvarious embodiments. Though depicted sequentially as a matter ofconvenience, at least some of the actions shown can be performed in adifferent order and/or performed in parallel. Additionally, someembodiments may perform only some of the actions shown. In someembodiments, the operations of FIG. 5, as well as other operationsdescribed herein, can be implemented as instructions stored in acomputer readable medium and executed by a processor.

In block 502, the GNSS system 110 is operating, for example receivingand processing navigation signals. The GNSS system 110 determineswhether a change in priority is desirable. For example if the GNSSsystem 110 determines that an increase in the signal-to-noise ratio(“SNR”) of received navigation signals is desirable, then the GNSSsystem can raise its priority. In some embodiments, the GNSS system 110can determine that a lower navigation signal SNR can be tolerated andlower GNSS system 110 priority accordingly. If the GNSS system 110determines that no change in priority is indicated, then GNSS system 110and wireless networking system 112 operations continue unchanged inblock 504.

If, in block 502, a priority change is indicated, then, in block 506,the wireless networking system 112 is notified of the change in GNSSsystem 110 priority. If the priority change raises GNSS system 110priority, then the wireless networking system 112 can act to reduceinterference with the GNSS system 110 by, for example, reducingtransmitter power output, increasing inter-transmission intervals, etc.If the priority change lowers GNSS system 110 priority, then thewireless networking system 112 can, for example, operate without regardfor the GNSS system 110.

In block 508, the GNSS system 110 determines a duration for the changedpriority. The duration may be based on, for example, an estimated timefor determining a reliable position estimate, or time until a nextposition estimate of a specified accuracy is needed.

In block 510, the GNSS system 112 determines whether the priority changeduration has expired. If the duration has expired, the method continuesin block 502, otherwise the method continues to check for expiration ofthe changed priority duration in block 510.

Table 1 below illustrates exemplary operation of the wireless networkingsystem 112 and the GNSS system 110 using the S1 216 signal, the S2 218signal, and the priority 220 signal. In this exemplary embodiment thesignals 216, 218, 220 are illustrated as indicating binary states. Thus,S1 216 indicates transmitter 206 active or inactive, S2 218 indicateswhether or not the receiver 204 is detecting transmitted signal, andpriority 220 indicates whether of not the GNSS system 110 has priority.

TABLE 1 Scenario S2 S1 Priority Active System 1 0 0 0 GNSS/WTX 2 0 0 1GNSS 3 0 1 0 WTX 4 0 1 1 GNSS 5 1 0 0 GNSS 6 1 0 1 GNSS 7 1 1 0 WTX 8 11 1 GNSS

Scenario 1 shows that no transmissions are being received by thewireless networking system 112 (“WTX”), and the GNSS system 110 has nopriority requirement. In this scenario, the GNSS system 110 can operatein ON/OFF mode at the interval of its choosing.

In scenario 2, the GNSS system 110 requests priority for a duration oftime. The wireless networking system 112 can modify its operation toaccommodate the priority request.

In scenario 3, S1 216 is asserted indicating that the wirelessnetworking system 112 requires priority. There is no priority requestfrom the GNSS system 110. Consequently, the transmitter 206 is activefor the duration of any required transmissions.

In scenario 4, the GNSS system 110 takes priority, because the priority220 signal is asserted. In this case, the wireless networking system 112is requested to minimize its interference with navigation signalreception.

In scenario 5, the wireless networking system 112 is receiving (S2 218is asserted), therefore, the GNSS system 110 can be active. In anembodiment in which the GNSS system 110 and the wireless networkingsystem 112 share a resource, for example receivers 204 and 214 sharecorrelators, some or all of the shared correlators can be allocated tothe receiver 204 for processing of network signals.

In scenario 6, the GNSS system 110 has priority because the priority 220signal is asserted.

In scenario 7, wireless networking system 112 gets priority. Scenario 7,where both S1 216 and S2 218 are asserted, may occur if the wirelessnetworking system 112 is transmitting, while at the same time anotherdevice 102, 106, 108 in the wireless network 100 is transmitting notknowing that wireless networking system 112 initiated transmission.

In scenario 8, GNSS system 110 gets priority because the priority 220signal is asserted. Accordingly, wireless networking system 112transmissions are managed to minimize interference.

As previously noted, the wireless networking system 112 can alsoindicate its operation frequency/band (or carrier frequency) to the GNSSsystem 110. The GNSS system 110 can use this information to furthermitigate interference.

The above discussion is meant to be illustrative of the principles andvarious embodiments of the present invention. Numerous variations andmodifications will become apparent to those skilled in the art once theabove disclosure is fully appreciated. It is intended that the followingclaims be interpreted to embrace all such variations and modifications.

What is claimed is:
 1. A method, comprising: determining whether awireless transmitter in a mobile wireless device has data to transmit;asserting a first interference level signal provided to a globalnavigation satellite system (“GNSS”) receiver in the mobile wirelessdevice by the wireless transmitter if the wireless transmitter has datato transmit; controlling the processing of navigation signals in theGNSS receiver based, at least in part, on the assertion of the firstinterference level signal by the wireless transmitter; determining thelocation of the GNSS receiver based on the navigation signal processing;and asserting a priority signal provided by the GNSS receiver to thewireless transmitter if the processing of navigation signals in the GNSSreceiver takes precedence over wireless transmitter transmissions. 2.The method of claim 1, further comprising: asserting a secondinterference level signal provided to the GNSS receiver by a wirelessnetwork receiver in the mobile wireless device if a wireless transmitternot colocated in the mobile device with the GNSS receiver istransmitting; and controlling the processing of navigation signals inthe GNSS receiver based on the assertion of the second interferencelevel signal by the wireless network receiver.
 3. The method of claim 2,further comprising allocating a hardware resource shared by the GNSSreceiver and the wireless network receiver colocated in the mobiledevice to one of the GNSS receiver and the wireless network receiverbased, at least in part, on the second interference signal.
 4. Themethod of claim 1, further comprising discontinuing processing ofnavigation signals in the GNSS receiver when the first interferencelevel signal is asserted.
 5. The method of claim 1, further comprisingapplying an interference mitigation technique in the GNSS receiver toreduce the effects of the wireless transmitter transmissions on thenavigation signals when the first interference level signal is asserted.6. The method of claim 1, further comprising improving navigation signalfidelity when the priority signal is asserted by one of reducingwireless transmitter transmission power and increasing wirelesstransmitter idle time relative to wireless transmitter active time.